Process for bleaching lignocellulose and pectocellulose.



A. R. DE VAINS.

PROCESS FOR BLEAGHING LIGNOOELLULOSE AND PEGTOGBLLULOSE.

APPLICATION FILED AUG. 1H 1913.

Patented Aug. 11, 1914;

bleaching under normal conditions.

ANTOINE REGNOUF DE VAINS, OF PARIS, FRANCE.

- PROCESS FOR BLEACHING LIGNocnLLUmsE AND PEcrocELLULosn.

Specification of Letters Patent.

Application filed August 18, 1913 Patented Aug. 11, 1914.

Serial No. 785,344.

To all whom it may concern:

Be it known that I, ANTOINE REGNOUF nu VAINS, a citizen of the French Republic, residing at 26 Rue de Naples, Paris, France, have invented new and useful Improvements in Process for Bleaching Lignocellulose and Pectocellulose, of which the following is a specification.

This invention relates to process for treating ligno-cellulose preparatory to bleaching, with a view to eliminating the ketones therefrom, and consists in the steps hereinafter described and claimed.

When it is desired to bleach ligno-cellulose by the usual processes, poo-r results are obtained, the cellulose not being white, but having a strong yellow tint owing to the ketones which it contains.

The present-invention relates to a process for submitting ligno-cellulose to a preliminar treatment so that it is rendered fitTior 1S process consists in eliminating the ketones which are contained in the material, and form the obstacle to ordinary bleaching. After having undergone this eliminating treatment, the cellulosecan be bleached in the usual manner by known means.

In principle, the characteristic of the process resides in the employment of chlorin in solution in order to eliminate the ketones contained in this kind of pulp. The chlorin in solution combines with the ketones and forms a soluble ketonic chlorid which can be removed by a simple Washing operation, thus leaving the cellulose in a pure condition which is submitted to ordinary bleaching by known processes.

In describing my invention reference will be had to the accompanying drawing wherein:

Figure l is a sectional view of an apparatus for carrying out the initial steps of the process; and Fig. 2 is a sectional View of an apparatus for carrying out the subsequent steps of the process.

Referring more particularly to Fig. 1 of the drawing, a designates a cylinder of reinforced concrete, the lower part of which is. connected to the upper by a lead pipe 6 comprising a pump 0. The material to be inserted is introduced by the opening cl and the chlorin in solution through the opening a and agitated by means of the pump 0. hen it is found, after a series of tests, that the chlorin has been well absorbed, the material 1s transferred to a washing machineof any suitable known type.

Referring to Fig. 2, the Washing machine is here shown to consist of a cylinder f of reinforced concrete having a false bottom 9 made of copper. A lead pipe h comprising a siphon k and provided with a cock k opens into the lower portion of the cylinder f. A pipe 2', provided with a cock 2', serves to introduce clean water. A lead pipe 7' comprising a pump 7" serves to establish communication between the top and bottom of the cylinder f. A pipe lo, having a cock la, serves to introduce the chlorinated material.

The material is poured into the cylinder f and the cook 72. is opened. "After the material has been drained sufiiciently, the cook 72. is shut and cock '5 is opened and clean water is introduced until the desired level is attained. The cock z" is then closed and the pump 7" is started. After some minutes water. The pump y" is then started again and is allowed to run for about half an hour, after which it is stopped again; the operation can be repeated if desired. The cellulose is flushed out of the cylinder f and placed in an ordinary bleaching engine in which, under the action of chlorid of lime it takes a beautiful bluish-white color. The proportions may be about 2 parts by weight of chlorid of lime to 100 parts by weight of cellulose.

Experiments have proved the economy resulting from the application of the present process as compared with the ordinary chlorid of lime process. For instance, with the ordinary process 860 kg. of chlorid of lime, that is 301 kg. of active chlorin were used to bleach 3226 kg. of asp-pulp, which corresponds to a consumption of 9.33 kg. of active chlorin per 100 kg, while by the process forming the subject of the present invention, in order to bleach 2992 kg. of an been proposed (Hoyer, Fabrication (Z6 Papz'er 1887, pages 128 and following and page 137) to use chlorin in solution as bleaching agent for normal cellulose pulps and that the result arrived at is the same as when using chlorid of lime. But chlorin in solution has never been used, as it is by applicant, for the preliminary treatment of ligno-cellulose, that is to say for the elimination of the ketones contained in certain kinds of pulps. In the first case the chlorin in solution acts as an oxidizing agent, while in applicants case, it acts as a halogen on a non-saturated compound.

I claim:

1. A process for treating ligno-ccllulose preparatory to bleaching for removing the ketones therefrom, which consists in subjecting the ligno-cellulose to the action of chlorin in solution for the purpose of forming a ketonic chlorid, and leaching to re move the ketonic chlorid.

2. A process for treating ligno-cellulose preparatory to bleaching for removing the ketoncs therefrom, which consists in subjecting the ligno-cellulose to the action of chlorin in solution for the purpose of forming a ketonic chlorid, leaching to remove the ketonic chlorid, and treating with alkaline water to assist the dissolution of the ketonic chlorid.

ANTOINE REGNOUF nu VAINS.

Witnesses:

LOUIS RINNY, HANSON C. Core 

